Usually, in many cases, polymerization reaction of poly-α-olefin using a metallocene catalyst are continuously performed, and the monomer conversion rate is about 30 to 70%. Under such circumstances, a still higher productivity has been desired.
For example, according to Patent Document 1, in the production technology of a conventional olefin-based polymer, the concentration of the olefin-based polymer at the time of the end of a reaction was 2 to 40 mass % in a polymerization reaction solution. In order to prevent an excessive polymerization reaction, an active proton-containing oxygen compound was added.
Moreover, in the production process of poly-α-olefin, in order to prevent excessive polymerization or to prevent deterioration of product quality, it is required to deactivate a catalyst after the end of a polymerization reaction to remove a metal component (decalcification).
For example, as the production method of poly-α-olefin, a method in which a crude product obtained after polymerization is brought into contact with a solid absorbent (alumina, acid clay, celite, or the like), thereby to absorb a catalyst residue, followed by filtration, or a method in which a compound having a hydroxyl group is added, thereby allowing a metal complex catalyst component to be unsoluble and removed is known (Patent Document 2). However, in this method, to remove a solid of several thousand to several hundred wt ppm by centrifugation or filtration, a large-sized centrifuge or a filtration machine is required, resulting in lowering of productivity.
Moreover, if a product was manufactured without the processing, a metal component was contained in the product in an amount of several ten to several hundred wt ppm.